FIG. 1 is a configuration diagram of an exhaust gas after-treatment apparatus in the related art. In general, as illustrated in FIG. 1, an after-treatment apparatus for exhaust gas generated in a diesel vehicle includes an exhaust gas oxidation catalyst part 10, an exhaust gas filtering part 20, a selective catalyst reducing part 30, an ammonia oxidation catalyst part 40, and the like that are disposed in this order.
Here, a dosing valve 31 is connected to a front side of a selective catalyst reducing part 30.
In the after-treatment apparatus and a process of using the after-treatment apparatus in the related art, the nitrogen compound reaches the selective catalyst reducing part 30 while the exhaust gas passes through the exhaust gas oxidation catalyst part 10 and the exhaust gas filtering part 20.
In this case, the after-treatment apparatus in the related art has a manner in which the exhaust gas enters the selective catalyst reducing part 30 regardless of a generated amount of the nitrogen compound. That is, there is a problem in that there is no structure which may control an inflow of gas into the selective catalyst reducing part 30 and an operation of the selective catalyst reducing part 30 on the basis of the generated amount of the nitrogen compound.
Accordingly, the selective catalyst reducing part 30 is continuously operated regardless of the generated amount of nitrogen compound even if the generated amount of nitrogen compound is small or there is no nitrogen compound, which causes a problem with deterioration in durability.
In addition, a location to which the nitrogen compound passing through the selective catalyst reducing part 30 flows is the ammonia oxidation catalyst part 40. The ammonia oxidation catalyst part 40 is a location where the ammonia is input and reacts with the nitrogen compound.
Even in this case, the ammonia oxidation catalyst part 40 is operated regardless of a rate of change of the nitrogen compound such that a problem with durability may occur, and this problem occurs because no detecting and calculating means, which may detect the nitrogen compound, is provided at a front side of the ammonia oxidation catalyst part 40.
Therefore, it is urgently needed to develop an apparatus having a structure in which determination to operate the selective catalyst reducing part 30 and the ammonia oxidation catalyst part 40 is performed on the basis of the generated amount or the rate of change of nitrogen compound.
The discussion above is merely provided for general background information and is not intended to be used as an aid in determining the scope of the claimed subject matter.